Indonesia's Mount Agung volcano erupts as seen from Amed, Karangasem, Bali, Indonesia November 26, 2017. [Photo/Agencies]

JAKARTA - Indonesia's disaster mitigation agency said on Monday it had raised the alert to the highest level four on Bali's Mount Agung volcano and warned residents in a 8-10 km (5-6 miles) radius around the volcano to evacuate immediately.

"Grey ash and occasional weak blasts can be heard 12 km (seven miles) from the peak. Flames were visible at night which indicates a potential eruption could happen anytime," Indonesia's disaster mitigation agency said in a statement.

"In anticipation of the possibility and imminent risk of disaster, PVMBG (the Volcanology and Geological Disaster Mitigation Centre) raised Mount Agung alert level from three to four starting from 6 a.m. local time," it said in a statement.